Tai seems to be the leader of the group, however, depending on either how demanding or
how how courageous he is, that is how Augumon will react. Like the time Augumon was the only one at the point who could digivolve further, because of Tai's attitude towards Augumon, he went from Greymon to SkullGreymon, because of Tai's bad treatment. If he feels the courage within, his crest begins to glow and then and only then can Greymon digivolve to Metal Greymon. But, no matter how bossy Tai gets, and no matter what he says to Augumon or the others, it's not too long before he realizes how wrong he is.